1. Technical Field
The present disclosure relates generally to robotics and, more particularly, to a robot arm assembly.
2. Description of Related Art
A commonly used industrial robot includes a fixed base, a frame pivotally connected thereto about a first rotation axis, a lower arm, in which one end of the lower arm is pivotally connected to the frame about a second rotation axis, and an upper arm, in which one end of the upper arm is pivotally connected to the other end of the lower arm about a third rotation axis. An end-effector, such as a welding device, a gripper or a cutting tool, is mounted at a distal end of the upper arm of the industrial robot to execute specific tasks. Generally, six axes are utilized to achieve maximum movement of the end-effector.
In robots of this kind, each arm rotates around a rotation axis driven by a driving unit. Typically, the driving unit includes a motor mounted on the lower arm and a speed reducer coupled to the motor to transmit the movement of the motor to the upper arm. However, the speed reducer generally has a relatively large volume and is positioned in the lower arm or the upper arm, thus the lower arm and the upper arm is relatively large. In addition, a weight of the upper arm is mainly applied on an output shaft of the speed reducer, thereby reducing the mechanism strength thereof.
Therefore, there is room for improvement within the art.